Acoustic 810 Woofers not working?

Discussion in 'Amps [BG]' started by mason326, Nov 7, 2012.


  1. mason326

    mason326

    Joined:
    Aug 2, 2006
    Location:
    Dallas, Texas
    Hey guys,

    I have an acoustic 810 and a B600H head that my parents got me as a graduation gift. Unfortunately, I had an issue with the original head just before warranty was out (after a 12mo song and dance, GC finally replaced it...) and now I have a new head. Problem is, when I plugged the darn things together, only the horn works! Zero power (or something) to the woofers. Any idea what might be wrong? Tried every dang button and knob on the head as well as different cables/cable types, to no avail, so I'm thinking it is the cab but no real clue here...

    Any help would be appreciated. Don't post on here often, and honestly haven't gotten to play much in the last four years. Darn school and work. :bag:
  2. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Do the battery test on the cabinet. If that fails then the amp took the voice coils with it when it blew.
  3. BogeyBass

    BogeyBass

    Joined:
    Sep 14, 2010
    only thing i could think of is broken or loose connections to the woofer section.

    Or most likely there is a low cost crossover for the tweeter, and the woofer portion of the crossover was damaged.

    Remove the jack plate on the 810 cab and see if your lucky they might have put a fuse on it for protection and you might have blown the fuse. sometimes its a inline fuse sometimes its a 1156 or 1157 12volt automotive lightbulb. 1156 will have 2 contacts (single bulb) and 1157 will have 3 contacts (dual element bulb for running and brake light)

    maybe try bypassing the crossover and do the battery test directly to a few of the speakers like Bassman Paul mentioned.
    if the crossover is bad...just dump the tweeter and run the speakers full range.
  4. mason326

    mason326

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    Aug 2, 2006
    Location:
    Dallas, Texas
    Thanks y'all, I'll give that a try and report back!
  5. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Good luck!
  6. SurferJoe46

    SurferJoe46

    Joined:
    Feb 22, 2010
    Location:
    The Bitterroot Mounts, Montana
    Some of the early Acoustic speakers had undersized spade connectors. I chased that problem in my B-450 and just went ahead and soldered pigtails on the drivers and haven't had a problem since.

    Check out the spade connexs - they are always suspect in these units.

    I've seen guys demand that GC refund their money on 'this cheap piece of junk' and I'd buy it and it takes me ten minutes to fix it.
  7. mason326

    mason326

    Joined:
    Aug 2, 2006
    Location:
    Dallas, Texas
    Well, I finally tore the thing apart. Not sure exactly what all I'm looking at, but something that struck me first was that there were four male connectors coming from the Speakon jack but only three wires attached to it going to the chip. Could this be the problem...? Don't think so, since the normal speaker cable jacks don't power the woofers either. Most of the solder contact points look good on the board.

    No visible fuse from what I could tell, but I'm no electrician. There is a small white box soldered into the chip though.

    Also, which wire am I supposed to do the battery test on now...?
  8. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Right across the terminals of each driver. If the cone fails to move the voice coils are open.
  9. SurferJoe46

    SurferJoe46

    Joined:
    Feb 22, 2010
    Location:
    The Bitterroot Mounts, Montana
    Remove the wires first.
  10. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    No need Joe. Each driver needs to be checking for cone movement. What the others do at the same time is irrelevant at the moment. If each cone moves properly it's time to go over the wiring. Finding the problem a final battery test to check that all the cones move in unison is the final step.
  11. SurferJoe46

    SurferJoe46

    Joined:
    Feb 22, 2010
    Location:
    The Bitterroot Mounts, Montana
    I was just thinking of not sending 9 volts back at the amp.

    Fixed the typo - sorry for 'bolts'.
  12. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Nothing should ever be done to a cabinet whilst it is connected to a working amp. I look at that as a given - others might not, so reasonable point. That said, removing wiring could easily lead to a miss-wire situation.
  13. SurferJoe46

    SurferJoe46

    Joined:
    Feb 22, 2010
    Location:
    The Bitterroot Mounts, Montana
    I usually tag all the wires.
  14. mason326

    mason326

    Joined:
    Aug 2, 2006
    Location:
    Dallas, Texas
    Not sure if I did it right, but 9v battery test directly on the terminals of one of the speakers yielded zero movement. Does that mean the voice coil is melted, at least in that one? Also, should I try bypassing the horn? Not sure how to re-wire in such a fashion...

    What is the best option if the voice coils are blown, buy new speakers or ditch the empty box and hope I can buy an ampeg in another ten years?
  15. SurferJoe46

    SurferJoe46

    Joined:
    Feb 22, 2010
    Location:
    The Bitterroot Mounts, Montana
    Personally, I'd tag all the wires and use a 1.5V battery to activate each driver individually.

    Testing them in the whole circuit, although somewhat indicative, won't find if only one driver is the cause of the problem.

    Make sure to disconnect any supply wires from the amp first - you don't want to be sending voltage into the output of any electrical device.
  16. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Sorry Joe but I disagree again. A 1.5V battery is on the low side to be able to see cone movement. 9V is ideal as the terminals of the battery are close to the spacing of the connetion strips of an average driver. If you connect the battery across those terminals and the cone doesn't move it's toast and you don't get more indicative than that. :)

    As regards voltage 100W is a tad over 28V into an 8Ω load. 9V is perfectly safe except for tweeters.
  17. SurferJoe46

    SurferJoe46

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    Feb 22, 2010
    Location:
    The Bitterroot Mounts, Montana
    I know - but as confused as the OP is, I thought I'd have to take into account that he might hit the tweeter too.

    Knowing that 1.5 V is on the low side, the driver will still give a moderate 'thump' with that voltage. Then armed with that info, it's a logical step to further inspection - that's all.
  18. RoadRanger

    RoadRanger Supporting Member

    Joined:
    Feb 18, 2004
    Location:
    NE CT
    Unfortunately a set of 8 Eminence B810's will run you more than the cab is worth ($75 each x 8 = $600). When those cabs were discontinued a short time ago I picked up a new one for $350 delivered :eek:. You should be able to find a used Ampeg 8x10 for what the new drivers would cost you...
  19. Fishheadjoe

    Fishheadjoe

    Joined:
    May 5, 2008
    Location:
    Toronto Canada
    I may be way off base here, but did the cab work ok before you replaced the head? Based on my reading of the OP, it seems all was well until the new head arrived.
    Do you have another head to try out the cab?
    How did your old head die?
    Seems odd that it worked (the cab) before you got the new head...
    Fishheadjoe
  20. 4StringShooter

    4StringShooter

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    Location:
    London, Ontario, Canada
    Disclosures:
    GBX Member #1
    Also: doesnt that head run at 2 Ohms???

    The Cab will be 4 Ohms???

    Am I off here.........

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